The present invention relates generally to a coupling quartz crystal resonator, and particularly to a GT-cut quartz crystal resonator in which plural longitudinal coupling modes are coupled and to a method for manufacturing the same.
Conventionally, an AT-cut quartz crystal resonator has been used for consumer products which require a resonator with excellent temperature characteristics and small CI (crystal impedance). Lately, in accordance with the miniaturization of various consumer products, miniaturization of the AT-cut quartz resonator has also been required. Miniaturization of this type resonator, however, is difficult because of the frequent occurrence of spurious vibrations and the resultant high CI. Unlike a tuning fork flexural quartz crystal resonator, it is difficult to minimize the size of the AT-cut quartz crystal resonator for use in a watch. Accordingly, a method of forming a resonator by photography which applies an IC technique has recently been applied to the manufacture, for example, of a tuning fork quartz crystal resonator and a GT-cut quartz crystal resonator (U.S. Pat. No. 4,350,918), and resultantly an extremely miniature resonator can be provided. However, U.S. Pat. No. 4,350,918 does not teach the electrode arrangement, a method for adjusting the frequency, a method for adjusting the temperature coefficient or the specific shape of the pedestal. On the contrary, the present invention discloses the above features.
Since, however, the GT-cut quartz resonator is supported at both ends, unlike the conventional type, it is necessary to improve the method for manufacturing the resonator unit. Accordingly, the present invention also provides a method for manufacturing a quartz crystal resonator unit having excellent shock resistance and frequency-temperature characteristics.